Red Marked

Though the Word Bearers’ attack on Calth and the subsequent Shadow Crusade into Ultramar are but a memory, the borders of Imperium Secundus are far from secure. Sergeant Aeonid Thiel, stranded on the garrison world of Oran on his way back to Macragge, frustrates his superiors once again by pointing out the holes in their defence – traitor warband activity is increasing, and a series of key listening posts have fallen silent. Leading a handful of rogue veterans and wearing the red mark of censure like a badge of honour, can Thiel uncover the truth behind the mysterious ‘Nightfane’?

After the war to save Ultramar from the traitor hosts of Horus ended, formerly disgraced Ultramarines Sergeant Aeonid Thielbelieves that enemies still linger within the borders of the empire. Finding other men of purpose, fellow Space Marines known as the ‘Red-Marked’, Thiel wages a guerrilla war to root out these enemies and vanquish them for good. Following the threads of a previous mission, the Red-Marked arrive on the moon of Bael. There they find an underwater rigging station that has seemingly been abandoned. But this place and its secrets could hold the key to the so-called ‘Nightfane’, a mysterious plot intended to bring about the destruction of Ultramar and only Thiel and his men can stop it.

那也就是一次小行动？我查Nightfane就查到这个广播剧...

在谈一下个人认为视频提到的几个关键时间点。
1.暗影远征之后，暗影远征结束于砍王在伊利瑞姆升魔之后。之后怀言者主力因嫌弃征服者号缺失导航员
速度过慢而独自离开，吞世者则四散成诸多小战帮，安格隆升魔后就游荡在奥特拉玛的边境星球大肆屠杀。被皮老板劝服后离开五百世界前往乌兰诺会师（黑暗之奴），此时期U团在地下战争，暗影远征等大战役结束后，黑暗天使到达之前已经基本稳定了奥特拉玛的局势，但边缘星球仍受叛徒侵扰。
2.第二帝国成立，根据小说不被铭记的帝国，第二帝国成立于暗影远征结束后两年左右，这个时期的忠诚派军力由于法罗斯灯塔引导而来的黑暗天使与血天使部队而到达最高峰，完全驱逐五百世界的叛军（小说death fire提到希尔军士就在带领部队追杀零散的叛徒战帮）的一系列行动的进行与强行突破毁灭风暴的战役准备是U团全面整合忠诚派前往泰拉的预备阶段。
3.毁灭风暴，自考斯之战的正式打响前——由怀言者用伊三伊五的忠诚者基因种子在考斯献祭而席卷奥特拉玛。第二帝国三巨头摧毁恶魔世界达文——战帅陨落之地后毁灭风暴消散。

我觉得只会讲到第二帝国成立，毕竟名字叫希望之死。

还有另外一点我不太清楚，黑暗机械教从机械奴工那里听到的“第32号甲板被开启，非法授权接入”以及他自己回答的“我们找到你了”，再到后面黑暗机械教向混沌怀言者星际战士报告后，混沌怀言者星际战士说“找到他，要活的”，是否表示仍旧有幸存的极限战士没有被消灭或者拘谨起来？ 从结尾看，U团老兵和冠军确实是被掉包了，因为当时他们的身后就站着两位混沌怀言者，看来这几位要么是想穿着U团的盔甲到处搞破坏，造成U团已经投身混沌的假象，要么就是想借此潜伏起来，到关键时刻再出手